Revision: 41463
http://brlcad.svn.sourceforge.net/brlcad/?rev=41463&view=rev
Author: r_weiss
Date: 2010-11-25 02:07:28 +0000 (Thu, 25 Nov 2010)
Log Message:
-----------
Made changes to functions bn_isect_line3_line3 and bn_coplanar. Updated most of
the tolerances in these functions using values determined by capturing values
during test runs and determining where the values converge to 0, 1, -1 etc.
These tolerances are not perfect and I believe these values should be computed
since they can vary. These tolerance changes appear to improve the results of
the mged 'ev' command and 'facetize' command and fewer error messages are
reported.
Modified Paths:
--------------
brlcad/trunk/src/libbn/plane.c
Modified: brlcad/trunk/src/libbn/plane.c
===================================================================
--- brlcad/trunk/src/libbn/plane.c 2010-11-24 20:37:44 UTC (rev 41462)
+++ brlcad/trunk/src/libbn/plane.c 2010-11-25 02:07:28 UTC (rev 41463)
@@ -1235,7 +1235,6 @@
int parallel = 0;
int colinear = 0;
-
BN_CK_TOL(tol);
if (NEAR_ZERO(MAGSQ(c), VUNITIZE_TOL) || NEAR_ZERO(MAGSQ(d),
VUNITIZE_TOL)) {
@@ -1254,11 +1253,12 @@
VCROSS(n, d, c);
det = VDOT(n, p) - VDOT(n, a);
- if (!NEAR_ZERO(det, SMALL_FASTF)) {
+
+ if (!NEAR_ZERO(det, 1.0e-10)) {
return -1; /* no intersection, lines not in same plane */
}
- if (NEAR_ZERO(MAGSQ(n), VUNITIZE_TOL)) {
+ if (NEAR_ZERO(MAGSQ(n), 1.0e-19)) {
/* lines are parallel, must find another way to get normal vector */
vect_t a_to_p;
@@ -1266,7 +1266,7 @@
VSUB2(a_to_p, p, a);
VCROSS(n, a_to_p, d);
- if (NEAR_ZERO(MAGSQ(n), VUNITIZE_TOL)) {
+ if (NEAR_ZERO(MAGSQ(n), 1.0e-19)) {
/* lines are parallel and colinear */
colinear = 1;
@@ -1274,7 +1274,7 @@
}
}
- if (NEAR_ZERO(MAGSQ(n), VUNITIZE_TOL)) {
+ if (NEAR_ZERO(MAGSQ(n), 1.0e-19)) {
bu_bomb("bn_isect_line3_line3(): ortho vector zero magnitude\n");
}
@@ -1370,11 +1370,9 @@
*/
VSUB2(h, a, p);
det = c[q] * d[r] - d[q] * c[r];
- det1 = (c[q] * h[r] - h[q] * c[r]); /* see below */
- /* XXX This should be no smaller than 1e-16. See
- * bn_isect_line2_line2 for details.
- */
- if (NEAR_ZERO(det, DETERMINANT_TOL)) {
+ det1 = (c[q] * h[r] - h[q] * c[r]);
+
+ if (NEAR_ZERO(det, 1.0e-10)) {
/* Lines are parallel */
if (!colinear || !NEAR_ZERO(det1, DETERMINANT_TOL)) {
return -2; /* parallel, not colinear, no intersection */
@@ -1420,15 +1418,9 @@
/* Check that these values of t and u satisfy the 3rd equation as
* well!
- *
- * XXX It isn't clear that "det" is exactly a model-space
- * distance.
*/
det = *t * d[s] - *u * c[s] - h[s];
- if (!NEAR_ZERO(det, SMALL_FASTF)) {
- /* XXX This tolerance needs to be much less loose than
- * SQRT_SMALL_FASTF. What about DETERMINANT_TOL?
- */
+ if (!NEAR_ZERO(det, 1.0e-23)) {
/* Inconsistent solution, lines miss each other */
return -1;
}
@@ -2244,15 +2236,16 @@
}
dot = VDOT(a, b);
+
VSCALE(pt_a, a, a[3]);
VSCALE(pt_b, b, b[3]);
- if (NEAR_ZERO(dot, SMALL_FASTF)) {
+ if (NEAR_ZERO(dot, 1.0e-8)) {
return 0; /* planes are perpendicular */
}
- /* parallel is when dot is within SMALL_FASTF of either -1 or 1 */
- if ((dot <= -SMALL_FASTF) ? (NEAR_ZERO(dot + 1.0, SMALL_FASTF)) :
(NEAR_ZERO(dot - 1.0, SMALL_FASTF))) {
+ /* parallel is when dot is within 4.5e-16 of either -1 or 1 */
+ if ((dot <= -SMALL_FASTF) ? (NEAR_ZERO(dot + 1.0, 4.5e-16)) :
(NEAR_ZERO(dot - 1.0, 4.5e-16))) {
if (bn_pt3_pt3_equal(pt_a, pt_b, tol)) {
/* test for coplanar */
if (dot >= SMALL_FASTF) {
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